JBL 2215b, le175, 2405 How do ?

[audi432]

I have JBL 2215b, le175, 2405. Help me! make crossover passiver. Thanks very much.

[Zilch]

Here's one approach:

http://audioheritage.org/vbulletin/showthread.php?t=9221

[toddalin]

Here's one approach:

http://audioheritage.org/vbulletin/showthread.php?t=9221

How appre po.

I just installed the second one yesterday. Had been so long, I had to take the first cabinet apart again just to see how I did it so I could make the wires in the second cabinet match. :o:

Now I need to retune the crossovers and do the install in the center cabinet.

I tried all the various combinations suggested by Zilch, with little change in sound, except that mid/tweeter could not play as loud, if asked to do so, and I actually went back to the original configuration that puts fewer parts in line with the tweeter (less can be better). Not shown in the schematic are the Theta by-pass caps that are in parallel with all caps shown. Also, we used the 12 watt Mills resistors (instead of the 10 watt values shown).

You could ignore the by-pass caps and use cheaper 10-watt resistors substantially reducing the approximate $135 each price to build these.

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Crossover.jpg





http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Crossover3.jpg

If you are using the 2405, use the .3 mH coils (as opposed to 0.5 mH shown) for the tweeter and conjugate mid.

[audi432]

Thank you very much. but jbl 2235 is 8ohm, 93db, my 2215b is 16ohm-96db; 175 is ohm; 2405 is 16ohm. My project: 2405 at 8khz up, 175 at 1.2khz-8khz, 2215b at 1.2khz down. May I offer a suggestion? Thanks

[Robh3606]

I would use the Lx-16 from the L200 and use the top section from the L300 to add the 2405. Basically you just adding a slot to the original L200. I believe the 175 and Le 85 have the same sensitivity.

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L200%20ts.pdf


http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L300%20Summit%20ts.pdf


Rob:)

[Mr. Widget]

I would use the Lx-16 from the L200...Rob, you seem to be thinking the 2215B is the equivalent to the LE15B... it isn't. It is the equivalent to the LE15A. The 2216 is the equivalent to the LE15B and the 2215A is a lower impedance variation on the LE15A. Yes, the JBL numbering system back then sure was confusing!

Do not use the LX-16...



Widget

[Zilch]

In that early numbering system, 2215B is 16 Ohms, no? It's an easy matter to adjust the LP component values accordingly.

2405 is actually 8 Ohms, no matter what it says on the foilcal, so not a concern. Todd has told you how to select the 8 kHz crossover point for the UHF, i.e., 0.3 mH in two locations, as shown on the schematic. Ideally, the crossover point for 2405 should be moved up to 10 kHz to sound best, and there are suggestions in these forums as to how to do that, but I haven't gotten around to working that out yet.

The remaining problem is moving from 800 Hz to 1.2 kHz, which is also accomplished by component value adjustment in the MF filter. You're changing the LP anyway, so adjust them to 1.2 kHz at the same time.

Do we know how well 2215B plays above 1 kHz? "Normally used below 800 Hz."

http://www.lansingheritage.org/html/jbl/specs/pro-comp/2215.htm

The most relevant posts from the "Keeper" thread:

http://audioheritage.org/vbulletin/showthread.php?p=93831&postcount=59

http://audioheritage.org/vbulletin/showthread.php?p=93836&postcount=62

http://audioheritage.org/vbulletin/showthread.php?p=105370&postcount=114

[Robh3606]

Thanks Widget

Your right I am thinking 2216 not 2215B. Can you get a 2215 up to 1.2K????

Rob:banghead:

[toddalin]

In that early numbering system, 2215B is 16 Ohms, no? It's an easy matter to adjust the LP component values accordingly.

2405 is actually 8 Ohms, no matter what it says on the foilcal, so not a concern. Todd has told you how to select the 8 kHz crossover point for the UHF, i.e., 0.3 mH in two locations, as shown on the schematic. Ideally, the crossover point for 2405 should be moved up to 10 kHz to sound best, and there are suggestions in these forums as to how to do that, but I haven't gotten around to working that out yet.

The remaining problem is moving from 800 Hz to 1.2 kHz, which is also accomplished by component value adjustment in the MF filter. You're changing the LP anyway, so adjust them to 1.2 kHz at the same time.

Do we know how well 2215B plays above 1 kHz? "Normally used below 800 Hz."

http://www.lansingheritage.org/html/jbl/specs/pro-comp/2215.htm

The most relevant posts from the "Keeper" thread:

http://audioheritage.org/vbulletin/showthread.php?p=93831&postcount=59

http://audioheritage.org/vbulletin/showthread.php?p=93836&postcount=62

http://audioheritage.org/vbulletin/showthread.php?p=105370&postcount=114

While moving the crossover point on the 2405 to 10 kHz is good for the tweeter, it may not be quite so good in terms of the LE175 (as opposed to the LE85) that begins to roll off sooner. Could probably just use a slightly smaller ~0.25 mH choke on the tweeter and congeguate mid or change the 1.5 mfd caps to 1 mfd units with reasonable success too.

[Mr. Widget]

In that early numbering system, 2215B is 16 Ohms, no?It is the same as the LE15A... they have called the LE15A both 16 ohms and 8 ohms. In free air there is am impedance rise of something like 70 ohms at Fs ~20Hz and a nominal impedance of 10 ohms. I have no idea what the curve for the 2215A (the lower impedance version also called the 8 ohm version) is like. There is no LE equivalent for this version.


Can you get a 2215 up to 1.2K????I am sure people have... I don't like it above about 500Hz. I must say that the LE15A/2215/2215B is a great sounding woofer between 40Hz and 500Hz.


Widget